export function addClass(el, className){
  if(hasClass(el,className)){
    return
  }
  let newClass = el.className.split('')
  newClass.push(className)
  el.className = newClass.join('')
}

export function hasClass(el, className){
  let reg = new RegExp('(^|\\s)' + className + '(\\s|$)')
  return reg.test(el.className)
}
